Brain games Brain training may increase your brain's 'RAM' but it won't improve your ability to solve problems, according to a new US study.

The findings suggest brain training will not lead to the "large and grandiose" rewards some have suggested, says co-author Tyler Harrison of the School of Psychology at Georgia Institute of Technology.

The idea that you can train the brain to improve intelligence is gaining popularity in the light of new findings on neuroplasticity, says Harrison.

It's argued that training to increase the capacity of your working memory (the equivalent of RAM in a computer) will also improve fluid intelligence (the ability to solve problems). The two are known to be closely correlated.

But, despite some studies claiming to provide evidence in support of brain training, Harrison argues there has been no good evidence to date that it improves working memory or intelligence.

"Right now I would say the field is very contentious," he says.

Strategies for working memory

In a typical brain training experiment, subjects are asked to recall an increasingly long string of digits or letters. But Harrison says it's possible for people to get better at recalling such strings by learning a strategy, such as mnemonics, rather than actually improving working memory.

He says previous studies had significant methodological flaws and were unable to distinguish between these two possibilities.

"None of them tested whether or not working memory capacity was actually being improved, which you would think would be critical to all of this," says Harrision.

In a new study, published in a recent issue of the journal Psychological Science, Harrison and colleagues specifically tested if working memory capacity was increased.

Participants were first trained to memorise a string of letters that got progressively longer. They were then tested for their ability to memorise a string of words and a string of arrows (pointing in different directions).

Compared to a control group, the trained group was able to remember longer strings of words and arrows.

Since a mnemonic or other strategy for memorising letters wouldn't help remembering words or arrows, the findings support the idea that the participants' working memory had indeed been improved by the training, says Harrision.

Because the study involved multitasking, the researchers say the findings suggest that such training can be used to improve the ability to multitask as well.

Intelligence tests

Before and after memory training, the participants were given different types of pattern recognition tests -- such as identifying the next number in a series or picking out an odd sequence of letters -- to see if their fluid intelligence increased.

A set of controls, who were given no working memory tasks, were tested in the same way.

However, no evidence was found that the training improved fluid intelligence, says Harrision.

He says there still needs to be a lot more research to support the effectiveness of brain training but the current findings suggest the rewards are more modest than the "large and grandiose" ones some have been suggesting, such as it could help cure ADHD.

Harrison says it has been a mistake to assume that because there is a strong correlation between working memory capacity and fluid intelligence that improving one will improve the other.

"Just because two things are highly related it doesn't mean there's a causal relationship between the two of them," he says.

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